Function unescape

parser/lexer/utils.go:15–55

Unescape takes a quoted string, unquotes, and unescapes it.

(value string)

// Unescape takes a quoted string, unquotes, and unescapes it.
func unescape(value string) (string, error) {
	// All strings normalize newlines to the \n representation.
	value = newlineNormalizer.Replace(value)
	n := len(value)

	// Nothing to unescape / decode.
	if n < 2 {
		return value, fmt.Errorf("unable to unescape string")
	}

	// Quoted string of some form, must have same first and last char.
	if value[0] != value[n-1] || (value[0] != '"' && value[0] != '\'') {
		return value, fmt.Errorf("unable to unescape string")
	}

	value = value[1 : n-1]

	// The string contains escape characters.
	// The following logic is adapted from `strconv/quote.go`
	var runeTmp [utf8.UTFMax]byte
	size := 3 * uint64(n) / 2
	if size >= math.MaxInt {
		return "", fmt.Errorf("too large string")
	}
	buf := new(strings.Builder)
	buf.Grow(int(size))
	for len(value) > 0 {
		c, multibyte, rest, err := unescapeChar(value)
		if err != nil {
			return "", err
		}
		value = rest
		if c < utf8.RuneSelf || !multibyte {
			buf.WriteByte(byte(c))
		} else {
			n := utf8.EncodeRune(runeTmp[:], c)
			buf.Write(runeTmp[:n])
		}
	}
	return buf.String(), nil
}

// unescapeBytes takes a quoted string, unquotes, and unescapes it as bytes.
func unescapeBytes(value string) (string, error) {